<template>
  <div class="spec-preview">
    <img v-lazy="skuImageList.imgUrl" />
    <div class="event" @mousemove="handleMove"></div>
    <div class="big">
      <img
        v-lazy="skuImageList.imgUrl"
        :style="{
          top: -2 * maskY + 'px',
          left: -2 * maskX + 'px',
        }"
      />
    </div>
    <div
      class="mask"
      :style="{
        top: maskY + 'px',
        left: maskX + 'px',
      }"
    ></div>
  </div>
</template>

<script>
//引入lodash中的节流功能
import { throttle } from "lodash";

export default {
  name: "Zoom",
  data() {
    return {
      maskX: 0,
      maskY: 0,
    };
  },
  props: {
    skuImageList: {
      type: Object,
      default: () => ({}),
    },
  },
  methods: {
    handleMove: throttle(function (e) {
      this.maskX = e.offsetX - 100;
      this.maskY = e.offsetY - 100;
      if (this.maskX < 0) {
        this.maskX = 0;
      } else if (this.maskX > 200) {
        this.maskX = 200;
      }
      if (this.maskY < 0) {
        this.maskY = 0;
      } else if (this.maskY > 200) {
        this.maskY = 200;
      }
    }, 1000/60),
  },
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>